1. Field of the Invention
This invention relates to an integrated circuit module suitable for the execution of logic operations on at least three input signals which appear together on inputs of the circuit, said circuit module having two supply lines for connection to a supply source, polarity supply lines having alternative sign, combinations of MOS transistors of at least one conductivity type connected therebetween, and also having signal lines for control of the state of conductivity of said MOS transistors.
2. Description of the Prior Art
Systems comprising MOS transistors of conductivity types which may or may not be mutually complementary are commonly used. A sub-category of such systems is that in which said MOS transistors comprise a layer of silicon nitride, originally used during the manufacture as a mask and being provided on a silicon substrate layer, electrically separating silicon oxide obtained from the semiconductor body being provided in openings in said deposited layer. This technology is known as the LOCMOS system, and is known from an article by B. B. M. Brandt et al, "LOCMOS a new technology for complementary MOS circuits", Philips Techn. Rev. 34, 1974, No. 1, pages 19-23. The combination of MOS transistors of opposite conductivity type offers advantages, because often a very low dissipation is achieved. Moreover, a high processing speed of the signals can be achieved, while a high packing density can be realized by the manufacturing technology described in said article. This can have a favourable effect on the processing speed.
Circuits of the kind described are often used to achieve an increasingly larger number of circuit elements per semiconductor chip, especially for microprocessors. Circuit modules of this kind are composed of elementary components such as logic gates which perform AND, OR, NAND, NOR and possibly other logic functions. The inputs of such gates usually have the same rank relative to each other, while a single logic function output is provided, possibly together with an output which is inverted with respect thereto. The invention has for its object to provide a system which can be readily designed by a computer. The technology described offers the possibility of improvement by arranging all transistors pair-wise, that is to say alternatively in one of two halves of a circuit. When a library of a number of cell modules is available, a computer can design a device by choosing cell modules from the library. The units of the library, however, appear to have a complex construction. Furthermore, it has been found that in many circuits the connections for signal transport between the various parts of a circuit occupy a large part of the area of the substrate layer, for example, up to 50%. The resultant larger surface area of the circuit is a drawback from a manufacturing point of view because of the inherently lower yield.